[JabavuAdams]

I may eventually do the same for a project I'm working on, although for me the draw would be UE's battle-tested network prediction code.

For visual programming in Unity, there's PlayMaker -- an add-on available from the asset store. It allows creation and graphical editing (and graphical runtime debugging) of FSMs (though not hierarchical FSMs). It's quite a good implementation of a FSM / event / action framework. It's basically superior to some tech I spent half of 2013 developing for an in-house proprietary engine.

I agree on the collaboration problems. Even with purely text-based serialization, collaboration is one of Unity's weak points.